<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            width: 100px;
            height: 100px;
            border: 1px solid red;
            /*给元素添加内边距会影响元素所占宽高*/
            padding-left: 50px;
            padding-top: 50px;
        }
    </style>
</head>
<body>
<div>ABC</div>
<ul style="padding: 0">
    <li>aaa</li>
    <li>aaa</li>
    <li>aaa</li>
</ul>

</body>
</html>